This paper analyses how many euro coins outflow from Germany and which composition of coins is to be expected in the long run. To this end, a simple mathematical model is formulated and calibrated for €1 coins. The introduction of the euro coins in 2002 presented a unique opportunity to analyse the cross-border migration and the mixing process of coins in different euro-area countries. Based on research by Stoyan and depending on growth assumptions, the annual outflow of German €1 coins is calculated to lie somewhere between 4% and 5%. In the long run, the ratio of German €1 coins in Germany is likely to converge to around 50%.